Interlock assembly for a vehicle transmission

Abstract

An interlock assembly for preventing more than one of a plurality of shift bars within a transmission shifter assembly from being moved out of a central neutral position at a given time is disclosed. An interlock bracket is connected to the lower end of the shift lever for movement therewith about a first or selecting axis. When the shift lever is moved so as to select a particular shift bar for movement, the interlock bracket moves therewith, thereby blocking movement of the non-selected shift bars. An interlock pin is connected to the interlock bracket for movement therewith. First and second springs are provided for urging the interlock pin, the interlock bracket, and the shift lever toward a centered position relative to the plurality of shift bars. The first spring resists movement of the shift lever out of the centered position in a first direction about the selecting axis, while the second spring resists movement of the shift lever out of the centered position in a second, opposite direction about the selecting axis. The first and second springs differ in size by a large amount so as to provide different magnitudes of tactile feedback to an operator of the shift lever. As a result, the operator can easily determine by "feel" which of the plurality of shift bars has been selected for subsequent movement to a gear engaging position.

What is claimed is: 
     
       1. In a vehicle transmission including a housing and a shift lever extending into the housing, a means for urging the shift lever toward a predetermined position within the housing comprising: an aperture formed through the housing, said aperture including a first diameter portion and a second diameter portion, a shoulder being defined between said first and second diameter portions;   a washer disposed in said first diameter portion of said aperture;   first spring means for urging said washer against said shoulder;   pin means having a first end thereof disposed in said second diameter portion of said aperture and a second end thereof being connected with the shift lever for movement therewith; and   second spring means for urging said first end of said pin means against said washer, the shift lever being positioned in the predetermined position when said washer engages said shoulder and said first end of said pin means engages said washer.   
     
     
       2. The invention defined in claim 1 wherein said first diameter portion of said aperture extends through to the exterior of said housing. 
     
     
       3. The invention defined in claim 2 further including plug means secured within said first diameter portion of said aperture adjacent to the exterior of said housing to close said aperture. 
     
     
       4. The invention defined in claim 3 wherein said first spring is disposed in said first diameter portion of said aperture between said plug means and said washer. 
     
     
       5. The invention defined in claim 1 wherein the diameter of said second diameter portion of said aperture is smaller than the diameter of said first diameter portion. 
     
     
       6. The invention defined in claim 1 wherein said first end of said pin means includes an enlarged head for journalling said first end of said pin means for axial movement in said second diameter portion of said aperture. 
     
     
       7. The invention defined in claim 6 wherein said shoulder is a first shoulder, and wherein said aperture further includes a third diameter portion which is smaller in diameter than said second diameter portion, a second shoulder being defined between said second and third diameter portions. 
     
     
       8. The invention defined in claim 7 wherein pin means is journalled for axial movement in said third diameter portion of said aperture. 
     
     
       9. The invention defined in claim 7 wherein said second spring means is disposed about said pin means and extends between said enlarged head of said pin means and said second shoulder for urging said head against said washer. 
     
     
       10. The invention defined in claim 1 wherein said pin means includes a pin having a first end disposed in said second diameter portion of said aperture and a second end connected to a bracket, said bracket being connected to the shift lever for movement therewith. 
     
     
       11. The invention defined in claim 10 wherein said second end of said pin is releasably connected to said bracket. 
     
     
       12. The invention defined in claim 11 wherein said bracket has a slot formed therein having a larger sized portion and a smaller sized portion, and wherein said second end of said pin has a reduced size neck portion defining an end portion cooperable with said bracket slot so as to be releasably securable thereto. 
     
     
       13. In a vehicle transmission including a housing containing a plurality of movable shift bars, a shift lever having a lower end extending into the housing for selecting one of the plurality of shift bars for movement, and an interlock bracket connected to the lower end of the shift lever for permitting movement only of the one shift bar selected for movement by the shift lever, a means for urging the interlock bracket toward a predetermined position relative to the shift bars comprising: an aperture formed through the housing, said aperture including a first diameter portion and a second diameter portion, a shoulder being defined between said first and second diameter portions;   a washer disposed in said first diameter portion of said aperture;   first spring means for urging said washer against said shoulder;   pin means having a first end thereof disposed in said second diameter portion of said aperture and a second end thereof being connected to the interlock bracket for movement therewith; and   second spring means for urging said first end of said pin means against said washer, the interlock bracket being positioned in the predetermined position when said washer engages said shoulder and said first end of said pin means engages said washer.   
     
     
       14. The invention defined in claim 13 wherein said pin means includes a pin having a first end disposed in said second diameter portion of said aperture and a second end connected to the interlock bracket. 
     
     
       15. The invention defined in claim 14 wherein said second end of said pin is releasably connected to the interlock bracket. 
     
     
       16. The invention defined in claim 15 wherein the interlock bracket has a slot formed therein having a larger sized portion and a smaller sized portion and wherein said second end of said pin has a reduced size neck portion defining an end portion cooperable with said interlock bracket slot so as to be releasably securable thereto. 
     
     
       17. The invention defined in claim 13 wherein said first diameter portion of said aperture extends through to the exterior of said housing. 
     
     
       18. The invention defined in claim 17 further including plug means secured within said first diameter portion of said aperture adjacent to the exterior of said housing to close said aperture. 
     
     
       19. The invention defined in claim 18 wherein said first spring is disposed in said first diameter portion of said aperture between said plug means and said washer. 
     
     
       20. The invention defined in claim 13 wherein the diameter of said second diameter portion of said aperture is smaller than the diameter of said first diameter portion. 
     
     
       21. The invention defined in claim 13 wherein said first end of said pin means includes an enlarged head for journalling said first end of said pin means for axial movement in said second diameter portion of said aperture. 
     
     
       22. The invention defined in claim 21 wherein said shoulder is a first shoulder, and wherein said aperture further includes a third diameter portion which is smaller in diameter than said second diameter portion, a second shoulder being defined between said second and third diameter portions. 
     
     
       23. The invention defined in claim 22 wherein pin means is journalled for axial movement in said third diameter portion of said aperture. 
     
     
       24. The invention defined in claim 22 wherein said second spring means is disposed about said pin means and extends between said enlarged head of said pin means and said second shoulder for urging said head against said washer.